JP5665653B2 - Double shoulder type tool joint - Google Patents

Description

  The present invention relates to a double shoulder type tool joint, and more particularly, to a double shoulder type tool joint that is excellent in water tightness even when repeated tightening and tightening are performed.

  Conventionally, drill pipes used for deep water drilling and horizontal well drilling are connected by a tool joint. Details of the tool joint are defined in API (American Petroleum Institute) standard 5DP. In order to transmit the high torque necessary for excavation, the outer diameter of the tool joint is formed with a diameter larger than the outer diameter of the tube body, and the inner diameter is formed with a diameter smaller than the inner diameter of the tube body, but there is a limit. The torque performance of the tool joint is generally low compared to the torque performance of the tube body portion. Therefore, in such a case, a double shoulder type tool joint has been proposed as a tool joint having high torque performance (for example, Patent Document 1).

  The tool joint described in Patent Document 1 is a double shoulder type tool joint, which is formed at one end of a drill pipe and has a female screw portion, and is formed at one end of another drill pipe, and has a male screw portion. It is a pipe joint which screws together with the pin provided with. The drill pipe is configured to sequentially connect the drill pipe by a tool joint including a box and a pin.

  The box has a box inlet sleeve formed parallel to the tip, a box inlet sleeve, a female thread formed with a predetermined taper, a parallel box end sleeve formed again, and an end of the box end sleeve. An inner shoulder formed at right angles to the tube axis, a tube inner diameter portion providing a hollow portion along the tube axis, and a box outer diameter portion forming an outer peripheral surface of the box. The pin has a pin nose having an outer peripheral surface parallel to the tube axis, a male screw portion formed following the pin nose and having the same taper as the box, and an outer peripheral surface parallel to the tube axis following the male screw portion. A pin base; an outer shoulder formed perpendicularly to the tube axis from the pin outer diameter; and a pin outer diameter forming an outer peripheral surface of the pin.

  The double shoulder type tool joint configured as described above has an inner peripheral surface of the box inlet sleeve and an outer peripheral surface of the pin base formed in parallel with the tube axis, and an inner peripheral surface of the box end sleeve and an outer peripheral surface of the pin nose. Is formed parallel to the tube axis, the thickness of the pin nose and the thickness of the box inlet sleeve can be made thicker than those of the conventional one. As a result, the contact area between the box inlet sleeve tip and the outer shoulder and the contact area between the pin nose tip and the inner shoulder can be increased, improving the torque resistance performance and extending the life of the tool joint. It is supposed to be possible.

Special table 2007-530875 gazette

  However, since the tool joint shoulder serves as a pressure receiving surface for tightening torque, it is difficult to maintain surface roughness and is not expected to be watertight by being repeatedly tightened by repeated use. In addition, the tool joint or a plurality of the tool joints may be leaned against the floor surface on the rig, the pin nose tip on the pin side may become the pressure receiving surface, and this inner pressure receiving surface may be damaged, There was a problem that sufficient water tightness was not exhibited in some cases.

  Accordingly, an object of the present invention is to provide a double shoulder type tool joint that is less susceptible to damage to the sealing surface (pin nose tip) of the tool joint and is excellent in water tightness when used in combination.

[1] In order to achieve the above object, the present invention has a box having a box outer diameter portion having a predetermined outer diameter, a tube inner diameter portion having a predetermined inner diameter, a first contact surface and an inner peripheral surface orthogonal to the tube axis. An inlet sleeve, a female thread portion having a predetermined taper with respect to the tube axis, a box end sleeve having a second contact surface and an inner peripheral surface orthogonal to the tube axis, A box provided with a third contact surface orthogonal to the tube axis at a portion advanced from the second contact surface; a pin outer diameter portion having a predetermined outer diameter; a tube inner diameter portion having a predetermined inner diameter; A pin base having a fourth contact surface in contact with the contact surface within an elastic range and an outer peripheral surface corresponding to the inner peripheral surface of the box inlet sleeve; a male screw portion engaged with the female screw portion; fifth contact to the perpendicular to the tube axis in contact with the elastic range on the contact surface Has a pin nose having an outer peripheral surface corresponding to the inner peripheral surface of the box end sleeve and, in the pin nose, contacted in elastic range to the third contact surface portion retracted from the contact surface of the fifth And a pin with a sixth contact surface orthogonal to the tube axis. A double shoulder type tool joint is provided.

  [2] The pin and the box are screw-engaged by the male screw portion and the female screw portion, and when tightened by the screw engagement, the first contact surface, the fourth contact surface, and the third The dimension of each contact surface is set so that the contact surface and the sixth contact surface, and the second contact surface and the fifth contact surface sequentially contact each other. The described double shoulder type tool joint may be used.

[3] The double shoulder according to the above [1] or [2], wherein a seal width between the sixth contact surface and the third contact surface is 1 mm to 2 mm. It may be a mold tool joint.

[4] The above [1] or [2], wherein the sixth contact surface is formed at a position 2 mm to 5 mm from the second contact surface (pin nose end surface) of the pin nose. It may be a double shoulder type tool joint described in 1.

[5] The double shoulder type according to [1] or [2], wherein the sixth contact surface and the third contact surface are each formed to have a surface roughness of 32S or less. It may be a tool joint.

  ADVANTAGE OF THE INVENTION According to this invention, the double shoulder type tool joint excellent in the watertightness at the time of connecting and using can be provided with the sealing surface (pin nose front-end | tip part) of a tool joint being hard to receive damage.

FIG. 1 is a diagram showing an entire double shoulder type tool joint and a drill pipe according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the double shoulder type tool joint according to the embodiment of the present invention along the tube axis of FIG. 3A is a partial detailed cross-sectional view of the pin nose, FIG. 3B is a partial detailed cross-sectional view of the box end sleeve, and FIG. 3C is a pin nose and box end in a state where the tool joint is fastened. It is a fragmentary detailed sectional view which shows the contact state of a part sleeve. 4A is an external view of a double shoulder type tool joint (drill pipe) according to the embodiment of the present invention, and FIG. 4B is a conventional double shoulder type tool joint (drill pipe) to be compared. FIG. FIG. 5 is a VME curve showing load conditions with the horizontal axis representing the load and the vertical axis representing the pressure.

(Embodiment of the present invention)
(Whole structure of tool joint and drill pipe)
FIG. 1 is a diagram showing an entire double shoulder type tool joint and a drill pipe according to an embodiment of the present invention. This double shoulder type tool joint 1 includes a box 2 formed at one end of a drill pipe 4 and provided with a female screw portion 23, and a pin 3 formed at one end of another drill pipe 4 and provided with a male screw portion 33. Is a pipe joint for screwing together. The drill pipe 4 is configured so that the drill pipe 4 is sequentially connected by a tool joint 1 including a box 2 and a pin 3.

(Tool joint configuration)
FIG. 2 is a cross-sectional view of the double shoulder type tool joint according to the embodiment of the present invention along the tube axis of FIG. The tool joint 1 includes a box 2 having a female screw portion 23 and a pin 3 having a male screw portion 33.

  The box 2 includes a box inlet sleeve 22 having a box inlet sleeve end surface 21 and an inner peripheral surface 22a, which are first contact surfaces orthogonal to the tube axis 50, and a female thread portion having a taper of 1/6 with respect to the tube axis 50. 23, a box end sleeve 24 having an inner surface shoulder end surface 25 which is a second contact surface orthogonal to the tube axis 50 and an inner peripheral surface 24a. A box seal surface 28, which is a third contact surface orthogonal to the tube axis 50, is provided at a portion advanced (in a direction from the inner shoulder end face 25 to the box inlet sleeve 22). In addition, a tube inner diameter portion 41 that provides a hollow portion along the tube axis 50 and a box outer diameter portion 26 that forms the outer peripheral surface of the box 2 are provided.

  The box outer diameter portion 26 is formed so as to gradually increase in diameter from the tube outer diameter portion 40 via the box side tapered shoulder 27. In FIG. 2, the screw portions of the female screw portion 23 and the male screw portion 33 are simplified to clearly show the taper. Here, the box inlet sleeve 22 and the box end sleeve 24 are illustrated as having an inner peripheral surface parallel to the tube axis 50, but are not limited thereto. The box inlet sleeve 22 and the box end sleeve 24 may have a taper smaller than the taper of the female screw portion 23 or the male screw portion 33, and particularly may be a taper of 1/12 or less with respect to the tube shaft 50. Further, in the present invention, the term “parallel” includes substantially parallel ones having such a small taper. Moreover, the right angle to the tube axis means not only a right angle but also a substantially right angle.

  The pin 3 includes a pin base 34 having an outer peripheral surface 34a corresponding to the inner peripheral surface 22a of the box inlet sleeve 22 and a female screw portion 23. The outer shoulder end surface 35 is a fourth contact surface that contacts the box inlet sleeve end surface 21. An outer peripheral surface corresponding to a male screw portion 33 that engages with the screw, a pin nose end surface 31 that is a fifth contact surface orthogonal to the tube shaft 50 that contacts the inner shoulder end surface 25, and an inner peripheral surface 24a of the box end sleeve 24. A pin nose 32 having a pin nose 32a. In this pin nose 32, a pin seal surface which is a sixth contact surface perpendicular to the tube axis 50 at a portion retracted from the pin nose end surface 31 (in a direction returning from the pin nose end surface 31 to the pin base 34). 38. In addition, a tube inner diameter portion 41 that provides a hollow portion along the tube shaft 50 and a pin outer diameter portion 36 that forms the outer peripheral surface of the pin 3 are provided.

  The pin outer diameter portion 36 is formed so as to gradually increase in diameter from the tube outer diameter portion 40 via the pin side tapered shoulder 37. Here, the pin nose 32 and the pin base 34 are illustrated as having an outer peripheral surface parallel to the tube axis 50, but are not limited thereto. The pin nose 32 and the pin base 34 may be any taper smaller than the taper of the female screw part 23 or the male screw part 33, and in particular, may be a taper of 1/12 or less with respect to the tube shaft 50.

  3A is a partial detailed sectional view of the pin nose 32, FIG. 3B is a partial detailed sectional view of the box end sleeve 24, and FIG. 3C is a pin nose 32 in a state where the tool joint is fastened. FIG. 5 is a partial detailed cross-sectional view showing a contact state between the box end sleeve 24 and the box.

  As shown in FIGS. 1, 2, and 3 (a), the tip end portion of the pin nose 32 has a pin nose end surface 31 that protrudes most and a pin seal surface 38 at a portion that retreats from the pin nose end surface 31 toward the pin base 34. Is formed. Both the pin nose end surface 31 and the pin seal surface 38 are planes orthogonal to the tube axis 50. Here, in a state where the drill pipe 4 is connected by screwing the female screw portion 23 of the box 2 and the male screw portion 33 of the pin 3, the pin seal surface 38 contacts in a state where surface pressure is applied by the tightening torque. In order to ensure a sealing function for maintaining the water tightness inside and outside the drill pipe 4, it is preferable that the surface is formed with a surface roughness of 32S or less.

  On the other hand, as shown in FIG. 3B, the box end sleeve 24 has a deepest inner shoulder end surface 25 and a box seal surface 28 at a position advanced from the inner shoulder end surface 25 toward the box inlet sleeve 22. Is formed. Both the inner shoulder end face 25 and the box seal face 28 are planes orthogonal to the tube axis 50. Here, in the state where the drill pipe 4 is connected by screwing the female screw portion 23 of the box 2 and the male screw portion 33 of the pin 3, the box seal surface 28 is in contact with the surface pressure applied by the tightening torque. In order to ensure a sealing function for maintaining the water tightness inside and outside the drill pipe 4, it is preferable that the surface is formed with a surface roughness of 32S or less.

  As shown in FIG. 3A, the dimension between the pin seal surface 38 and the pin nose end face 31 is L1, and the dimension between the box seal face 28 and the inner shoulder end face 25 is as shown in FIG. Let L2. When the drill pipe 4 is connected, as the male threaded portion 33 is screwed into the female threaded portion 23, the outer shoulder end face 35 first contacts the box inlet sleeve end face 21, and then the pin seal face 38 contacts the box seal face 28. By further screwing, the pin nose end face 31 and the inner shoulder end face 25 come into contact with each other. In this way, L1 <L2 is set so as to sequentially contact each other. Here, the dimensions L1 and L2 are set in a range of 2 mm to 5 mm. This is because even if the drill pipe 4 is leaned against the floor surface on the rig, the pin seal surface 38 is less likely to be damaged such as deformation and dents. If the tolerances of L1 and L2 are both ± 0.01 mm, the dimension L2> L1 + 0.02 mm is formed so that L1 <L2.

  The width where the pin seal surface 38 and the box seal surface 28 come into contact, that is, the seal width W shown in FIG. 3C is preferably set to 1 mm to 2 mm. This is to ensure water tightness and to prevent poor contact such as per piece. Here, the seal width W is a dimension excluding the R portion formed at the corner and the C chamfered portion formed at the corner.

  Further, as shown in FIG. 3C, the width of the gap (pin nose gap) between the outer peripheral surface 32a of the pin nose 32 and the inner peripheral surface 24a of the box end sleeve 24 is configured to be 0.5 mm or more. Similarly, the width of the gap (pin base gap) between the outer peripheral surface 34a of the pin base 34 and the inner peripheral surface 22a of the box inlet sleeve 22 is configured to be 0.5 mm or more. When the drill pipe 4 is sequentially connected by the box 2 and the pin 3, the dimension is an appropriate dimension which does not damage the structure while maximizing the strength of the structure.

(Dimension example)
The dimension example of each part shown above is, for example, a drill having a drill pipe 4 having an overall length of ~ 13500 mm, a pipe outer diameter of 60.2 mm to 168.3 mm, an inner diameter of 38.1 mm to 127.0 mm, and a pin nose length of 12.7 mm to 38.1 mm Can be applied to pipes.

  The material of the box 2 and the pin 3 is not particularly limited as long as it has strength that conforms to the provisions of the API standard 5DP.

(Tool joint connection)
The box 2 and the pin 3 are screw-engaged by the female screw portion 23 and the male screw portion 33. When the box 2 and the pin 3 are tightened by screw engagement, the box inlet sleeve end face 21 and the outer shoulder end face 35, the box seal face 28 and the pin seal face 38 are secured. The dimension of each contact surface is set so that the inner shoulder end surface 25 and the pin nose end surface 31 are in contact with each other. In order to connect a plurality of drill pipes 4 using the tool joint 1 having such dimensions, first, the box 2 and the pin 3 are opposed to each other, and the tip of the pin 3 is placed in the opening of the box 2. , And / or rotate the box 2 and / or the pin 3 so that the box inlet sleeve end face 21 and the outer shoulder end face 35 are in contact, then the box seal face 28 and the pin seal face 38 are in contact, and the inner shoulder Fastening is performed until the part end face 25 and the pin nose end face 31 come into sequential contact.

  Here, the surface that the inner shoulder end surface 25 closest to the tube inner diameter portion 41 contacts with the pin nose end surface 31 functions as an inner pressure receiving surface. The contact surface between the pin seal surface 38 and the box seal surface 28 located in parallel near the contact surface between the inner shoulder end surface 25 and the pin nose end surface 31 functions as a seal surface. Further, the surface of the box inlet sleeve end surface 21 and the outer surface shoulder end surface 35 that is closest to the tube outer diameter portion 40 functions as an outer pressure receiving surface.

(Tightening / Tightening test)
The performance evaluation of the tool joint 1 according to the embodiment of the present invention, that is, a double shoulder type drill pipe with a seal type is compared with a double shoulder type drill pipe without a seal type without a pin seal surface and a box seal surface. While doing so.

  4A is an external view of a double shoulder type tool joint (drill pipe) according to the embodiment of the present invention, and FIG. 4B is a conventional double shoulder type tool joint (drill pipe) to be compared. FIG. As shown in FIG. 4A, in the double shoulder type tool joint according to the embodiment of the present invention, a pin seal surface 38 is formed at a portion retreated from the pin nose end surface 31 at the tip portion of the pin nose 32. On the other hand, in the double shoulder type tool joint as a comparative example, the tip end portion of the pin nose 32 is a pin nose end surface, and there is no portion corresponding to the pin seal surface.

  The test results for performance evaluation are shown below. Before the pressure test, 50 times in order to give water- and air-tight pin seal surfaces, box seal surfaces, pin nose end surfaces and inner shoulder end surfaces equivalent to actual work. Tightening and rewinding are performed in advance. 50 tightening / rewinding tests were completed and baking was performed. This is to eliminate the influence on the sealing performance of the lubricant used during tightening / retightening. The internal pressure / tensile combined load test including the bending load was performed on the two test bodies shown in FIGS. Thereby, the superiority of the internal pressure resistance due to the sealing effect by the contact between the box seal surface 28 and the pin seal surface 38 is confirmed.

  FIG. 5 is a VME curve showing load conditions with the horizontal axis representing the load (Axial Load) and the vertical axis representing the pressure (Pressure).

(Test conditions)
As test conditions, along the VME curve shown in FIG. 5, the leak occurrence point from the joint when the internal pressure is increased from LP (Load Point) 1 to LP13 is investigated. When applying a load from LP2 to LP2B, only the bending load (7.5 ° / 100 ft) is applied to LP2B. Thereafter, the internal pressure is increased at 2000 psi / step.

(Test results)
[Specimen No. 1 (with seal)]
Specimen No. shown in FIG. 1 (double shoulder type tool joint according to the present invention) does not leak.
Final LP13: Total axial load 289.0kips (131tonf), Tensile load 150.1kips (68tonf), Internal pressure 27000psi (186.2MPa)
The test was terminated due to the limitations of the test facility FST.

[Specimen No. 2 (no seal)]
Specimen No. shown in FIG. 2 (conventional double shoulder type tool joint) leaked at LP6.
LP6: Total axial load 474.5kips (215tonf), tensile load 397.3kips (180tonf), internal pressure 15000psi (103.4MPa)
Actually, a pressure drop was observed at LP5 (tensile load: 483.5 kips, internal pressure: 13000 psi) one step before.

(Effect of embodiment)
The embodiment of the present invention has the following effects.
(1) Since the pin seal surface 38, which is the seal surface, is provided in a portion (another surface) that is retreated from the pin nose end surface 31, the pin seal surface 38 is not continuous with the end surface pressure receiving surface of the pipe. Even if it is leaned against the floor surface, the sealing surface does not collide and damage, and it is difficult to be damaged from the side.
(2) The pin seal surface 38 and the box seal surface 28 are in contact with each other separately from the contact surface of the inner shoulder end surface 25 and the pin nose end surface 31 that function as the inner pressure receiving surface. There is no need for strict dimensional control for management. Furthermore, since the sealing surface is perpendicular to the tube axis, it is not necessary to prepare a special measuring instrument because it is easy to measure dimensions during manufacture, rather than a spherical or oblique sealing surface.
(3) In the DSJJ (double shoulder type tool joint) technology, the outer pressure receiving surface (the outer pressure receiving surface where the box inlet sleeve end surface 21 and the outer shoulder end surface 35 contact) is first hit by the same tightening torque as before. The inner pressure receiving surface (the inner pressure receiving surface where the inner shoulder end surface 25 and the pin nose end surface 31 come into contact) hits. At this time, the seal surface, which is the contact surface between the pin seal surface 38 and the box seal surface 28 of the present invention, is located in a region that is as close as possible to the inner pressure receiving surface. Accordingly, it is possible to make the structure difficult to be damaged while maintaining the strength of the tip of the pin, and to reliably suppress the leak due to the increase in internal pressure. Thereby, the double shoulder type tool joint excellent in watertightness when connected and used can be provided because the sealing surface (pin nose tip) of the tool joint is not easily damaged.
(4) Tool width that can withstand an internal pressure of an average excavation drilling mud pressure of 7000 psi by setting the seal width: 1 mm to 2 mm, the step from the inner pressure receiving surface to the seal surface: 2 mm to 5 mm, and the roughness of the seal surface: within 32S. Drill pipes are possible.
(5) The water hole is a large opening that repeats erosion due to hydraulic pressure, with through holes such as gaps and fatigue cracks as leaking routes, reducing drilling efficiency of the drill pipe tip bit due to pressure loss, or breaking the water hole Leads to large operational troubles and time loss. However, since it has a seal surface by the pin seal surface 38 and the box seal surface 28 in addition to the inner pressure receiving surface, the generation of water holes can be suppressed by the sealing performance, the operation trouble of the rig is prevented, the downtime is shortened and the drill pipe It is possible to improve the lifetime of the device itself.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from or changing the technical idea of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Tool joint 2 ... Box 3 ... Pin 4 ... Drill pipe 21 ... Box inlet sleeve end surface 22 ... Box inlet sleeve 22a ... Inner peripheral surface 23 ... Female thread part 24 ... Box end sleeve 24a ... Inner peripheral surface 25 ... Inner surface shoulder End face 26 ... Box outer diameter part 27 ... Box side taper shoulder 28 ... Box seal face 31 ... Pin nose end face 32 ... Pin nose 32a ... Outer peripheral face 33 ... Male screw part 34 ... Pin base 34a ... Outer peripheral face 35 ... Outer shoulder end face 36 ... Pin outer diameter part 37 ... Pin side taper shoulder 38 ... Pin seal surface 41 ... Pipe inner diameter part 50 ... Pipe shaft

Claims (5)

A box outer diameter portion having a predetermined outer diameter, a tube inner diameter portion having a predetermined inner diameter, a box inlet sleeve having a first contact surface and an inner peripheral surface orthogonal to the tube axis, and a female having a predetermined taper with respect to the tube axis A box end sleeve having a threaded portion, a second contact surface orthogonal to the tube axis, and an inner peripheral surface; and in the box end sleeve, the tube shaft is moved to a portion advanced from the second contact surface. A box with an orthogonal third contact surface;
A pin outer diameter portion having a predetermined outer diameter, a tube inner diameter portion having a predetermined inner diameter, a fourth contact surface contacting the first contact surface within an elastic range, and an outer periphery corresponding to the inner peripheral surface of the box inlet sleeve A pin base having a surface, a male threaded portion engaging with the female threaded portion, a fifth contact surface perpendicular to the tube axis contacting the second contact surface within an elastic range, and a box end sleeve A pin nose having an outer peripheral surface corresponding to the inner peripheral surface, wherein the pin nose is orthogonal to the tube axis that is in contact with the third contact surface within an elastic range at a portion retracted from the fifth contact surface; A pin with a sixth contact surface;
A double shoulder type tool joint characterized by comprising:   The pin and the box are screw-engaged by the male screw portion and the female screw portion, and when tightened by the screw engagement, the first contact surface, the fourth contact surface, and the third contact surface 2. The double shoulder according to claim 1, wherein dimensions of the contact surfaces are set so that the second contact surface, the sixth contact surface, the second contact surface, and the fifth contact surface sequentially contact each other. Mold tool joint.   The double shoulder type tool joint according to claim 1 or 2, wherein a seal width between the sixth contact surface and the third contact surface is 1 mm to 2 mm.   The double shoulder type tool joint according to claim 1 or 2, wherein the sixth contact surface is formed at a position of 2 mm to 5 mm from the second contact surface (pin nose end surface) of the pin nose. . The double shoulder type tool joint according to claim 1 or 2, wherein the sixth contact surface and the third contact surface are each formed to have a surface roughness of 32S or less.